Elastic-fluid turbine



Inventor-zv Wi l I i am I-LAtKi nson Hits-Attorney.

Patented Feb. 8, 1927.

FFECE.

WILLIAM H. ATKINSON, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A. CORPORATION OF NEW YORK.

ELASTIC-FLUID TURBINE.

Application -led August 30, 1922, Serial No. 585,222. Renewed January 29, 1926.

The present invention relates to elastic fluid turbines of the impulse or reaction type and more particularly to the stationary fluid directing means.

The object I have in view is to construct the stationary fluid directing means of a steam turbine .in such a manner that the sudden and violent impacts of the steam jets upon the moving buckets will be reduced to a minimum and also to improve their etficiency.

In steam turbines as at present constructed.

the nozzles are designed so as to direct a solid jet of steam over the whole length ot' the buckets, the nozzle-mouthbeing radial, or parallel to the bucket into which it discharges. As Will be clearly seen the buckets of a turbine of this type will be subject to a series of impacts or impulses corresponding in number to the number of jets through which they travel. These impacts or impulses may often have a tendency to set up undesirable vibrations in the bucket wheel.

Furthermore, with the usual radial nozzles and intermediates, the moving buckets are alternately filled with high velocity elastic iiuid from the centers ot' the nozzle jets and with low velocity elastic fluid from the outer portions oi the nozzle jets, which portions flow along the surfaces of thc nozzle plates or partitions. The resulting intermittent iiow has a tendency to produce eddy currents and corresponding losses accompanied by a periodical fluctuation in the force exerted on the buckets by the elastic fluid.

Vhile I have confined my statements to the conditions adjacent the nozzles and first row of buckets it is evident that the same conditions will exist between all the succeeding rows of intermediates. or stationary buckets and moving buckets of each stage, as the stationary buckets are the equivalent or nozzles in that they will again redirect the steam in a series of jets upon the next adjacent set of moving buckets and thus aggravate the condition spoken of above.

In the accompanying drawings, which are illustrative of my invention, Fig. 1 is a partial perspective view of a turbine in which my invention is used. It shows the manner of inclining the nozzles and stationary intermediate buckets; Fig. 2 shows a modiiication of my invention where only one side of the nozzle mouth is inclined; Fig. 3 is a partial plan view ot' the nozzles and buckets shown in Fig. 1. It shows the relative positions and proportions of the parts with respect to each other.

Referring now to Figs. 1 and 3 of the drawings; in carrying out my invention I provide nozzles- 10 carried in a fixed nozzle plate 11 and having their discharge orifices or mouths inclined at an angle a with respect to adjacent radial buckets 12 or radial line, A-A Fig. 1. The buckets are mounted on a rotating or moving element such as a suitable rotor or rotor wheel indicated at 13. The angle a (Fig. 1) is such that the jet from a single nozzle 10 will discharge against at least two buckets 12 at one time. I also provide that the nozzles 10 lap each other so as to admit practically the same amount of steam to the buckets 12 as is the case where the mouths of the nozzles 10 are radially arranged or parallel with the buckets 12. This arrangement will give a substantially steady flow of steam to the buckets 12 and thereby eliminate the intermittent or pulsating effect which the jets from radial nozzles would have upon the buckets 12. In addition to inclining the mouths of the nozzles 10 I also incline the intermediate or stationary buckets indicated at 15 at an angle a with respect to the radial line B-B. The intermediate buckets are mounted in a fixed ring 14. As has been stated above the intermediate buckets are the equivalent of. the nozzles 10 in their effect on the next adjacent set of buckets indicated at 16. Buckets 16 are, in the present example, carried by rotor wheel 13 along with buckets 12. The intermediate buckets 15 are inclined at substantially the same angle as the nozzles 10 and should discharge on at least two of the rotating buckets 16. at the same time.

Thus both the nozzles and the intermediate buckets serve as means or passages through which elastic fluid is directed to the moving buckets, the radially outer por tions of the passages being in advance, as regards the direction of rotation of the wheel or rotor, of the radially inner portions thereof sufficiently to provide delivery of elastic fluid by each fluid directing passage into more than one bucket, that is, into at least two as hereinbefore stated.

Viewed in another aspect, the arrange ment is such that the projection of the exit or discharge edge of each nozzle partition and of each intermediate blade on the surface in which the inlet or entrant edges of the moving buckets lie, cuts or intersects at least two of said moving bucket edges for each position of the rotor wheel, that is, the inlet edge of each moving bucket is at all times intersected by the projections, on a surface common to all of said inlet edges, of at least two adjacent nozzle or fixed intermediate bucket exit or discharge edges.

Considering one jet and following it through the turbine it will be seen that as it leaves the mouth of one of the nozzles 10 it will first strike the adjacent bucket 12 at a pointnear its base and strongest point. As the bucket 12 moves past the nozzle l0 the jet will strike points along the bucket 12 toward its upper end. The jet at this upper point of the bucket 12 will have a smaller velocity than at the base because of the spreading of the jet which occurs at the tail of practically all nozzles. As a result of this spreading of the jet the strain upon the bucket at a point where it is weak will be reduced. lVhile this relatively reduced force is being applied at its weak point a stronger force is being eX- erted at the base or strong point of this same bucket by reason of the jet of steam from the next adjacent nozzle, thus completely covering the bucket 12 with moving steam. The steam as it is discharged from the nozzle 10 has in addition to its axial velocity, a tangential velocity due to the direction of discharge from the nozzle 10 which will with the usual radial nozzle, have a tendency to cause some of the steam to travel outwardly around the ends of the moving buckets 12 and 16 and thus reduce the amount of steam for doing useful work. As the steam is vdischarged from the moving buckets 12 it will be taken up by the stationary intermediates or buckets 15 and due to the inclination of these stationary intermediates or buckets l5 the steam will be redirected into the next row of moving buckets 16 inwardly in a useful direction and against their bases as is the case where the jet issues from the nozzles proper.

In the modification shown in Fig. 2 I have shown only the nozzles 10 and adjacent moving buckets 12 mounted on the rotor 13. It should be understood, however,

that I may or may not as conditions warrant, use the inclined intermediates or stationary buckets described above in connection with Fig. l, in a turbine having nozzles 10 of the shape shown in Fig. 2. In a turbine having` nozzles in accordance with this modification the steam as it is discharged from the nozzles 10 will first strike the buckets 12 as they rotate, at a point near their bases and wipe outwardly until each bucket receives steam throughout its whole length, that is while one bucket is receiving a jet of steam a small portion of the same jet will strike the next following` bucket and in that way the sudden impacts or impulses which would be caused by a full jet of steam suddenly striking each bucket will be eliminated. y

rlhis arrangement is in effect similar to that provided in the previously-described en'ibodin'ient in which the radially outer portions of the nozzle passages are displaced by the angle a in advance of the radially inner portions thereof.

From the foregoing description it will be seen that a nozzle arrangement provided in accordance with the invention effects a material reduction 0f eddy losses hereinbefore mentioned, since the moving buckets will at all times be filled in part by the high velocitv elastic fluid from the centers of the nozzle jets and in part by the low velocity elastic fiuid from the outer portions of the nozzle jets instead of meeting intermittent high velocity and low velocity flow. This provides for a material reduction of the impact or impulse effect upon the buckets since each bucket instead of receiving the full impact or impulse of a jet of steam over its whole length at one time will receive only a small impact or impulse at its base which will gradually` increase in magnitude depending upon the angle of inclination of the near-side of the nozzle 10. By near-side of the nozzle 1() I mean that side which is nearest the approaching bucket 12.

That I claim as new and desire to secure by Letters Patent of the United States, is

l. In an elastic-fluid turbine, the combination of nozzles and moving buckets, said nozzles being inclined at an angle with respect to the moving buckets into which they discharge, said angle being such that each bucket receives elastic fluid from at least two nozzles at all times while moving adjacent said nozzles.

2. In an elastic-fluid turbine, the combination of moving buckets, and nozzles and stationary intermediate buckets inclined at an angle and in planes parallel to the moving buckets, said nozzles and stationary intermediate buckets being thereby positioned to discharge a plurality of jets of elastic fluid into each of said moving buckets at one time.

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3. In an elastic-fluid turbine, the combination of moving buckets having inlet edges for receiving elastic fluid, a rotating member upon which said buckets are mounted, and nozzles having exit edges inclined at an angle with respect to adjacent bucket edges for directing a jet of fluid upon at least two buckets at the same time, whereby said jet of fluid strikes different points on the respective buckets substantially as described.

t. In an elastic fluid turbine the combination of rows of moving buckets, and intermediate stationary buckets located between said rows of moving buckets, said intermediate buckets being inclined at an angle with respect to the moving buckets and in the direction of rotation of said moving buckets to thereby redirect the elastic fluid inwardly against the buckets into which they discharge.

5. In an elastic fluid turbine, a rotor, an annular row of buckets carried thereby, said buckets having elastic fluid inlet edges which move in a common annular path, a stationary nozzle means adjacent said bucket row having fluid directing eXit edges which lie in an annular' surface adjacent the annular path of movement of the bucket inlet edges, said fluid directing edges being disposed at an angle with respect to the inlet edges of adj acent buckets whereby each of said fluid directing edges is positioned to deliver elastic fluid upon at least two of said inlet edges.

6. In an elastic-fluid turbine, the combination of moving buckets and stationary fluiddirecting nozzles therefor, said nozzles being inclined in the direction of movement of the buckets and being thereby adapted to discharge a plurality of jets of elastic fluid into each of said moving buckets.

7. In an elastic fluid turbine, the combination of an elastic fluid directing nozzle means, and buckets which move adjacent thereto, said nozzle means providing nozzle passages having exit edges which in projection intersect the adjacent bucket edges.

8. In an elastic fluid turbine, the combination of an elastic fluid directing nozzle means, and buckets which move adjacent thereto, said nozzle means providing nozzle passages having exit edges which in projection intersect at least two adjacent bucket edges.

9. In an elastic-fluid turbine, moving substantially radial buckets and a plurality of fluid-directing nozzles therefor arranged adjacent to each other, the nozzles being inclined so as to lap one another with respect to a radial line passing through them, whereby said nozzles direct a plurality of jets of elastic fluid into each of said moving buckets.

l0. In an elastic fluid turbine of the axial flow type the combination of stationary nozzles, and moving buckets having inlet edges which receive elastic fluid from the nozzles, said nozzles having exit edges displaced at an angle with respect to the inlet edges of adjacent buckets whereby said nozzles first direct a small volume of fluid against the bases of said moving buckets and gradually increase the volume of fluid therein as the buckets move with respect to said nozzles.

11. An elastic fluid turbine having moving buckets, nozzles and stationary intermediate buckets, characterized by the fact that the nozzles and stationary intermediate buckets are adapted to discharge into more than one bucket at one time and gradually apply the propelling jet of elastic fluid to said moving buckets.

12. An elastic fluid turbine comprising moving blades and fluid directing means for directing elastic fluid to the blades, characterized by the fact that the fluid directing means are so shaped as to discharge elastic fluid into two or more blades at different points along their lengths.

13. In an elastic fluid turbine, the combination with a rotor having an annular ring of buckets, each of which is provided with a substantially radial inlet edge for the reception of elastic fluid, of a fixed nozzle means adjacent said ring of buckets for directing elastic fluid therethrough, said nozzle means providing a plurality of nozzle passages having exit edges, the projections of which on the surface in which the inlet edges of the buckets lie, intersect adjacent inlet edges of said buckets.

14. In an elastic fluid turbine, the combination with a rotor having an annular ring yof buckets, each of which is provided with a substantially radial inlet edge for the reception of elastic fluid, of a fixed nozzle means adjacent said ring of buckets for directing elastic fluid therethrough, said nozzle means providing a plurality of nozzle passages having exit edges, the projections of which 0n the surface in which the entrant edges of the buckets lie, intersect not less than two adjacent inlet edges of said buckets.

15. In an elastic fluid turbine, the combination with a rotor having an annular ring ofbuckets secured thereon, said buckets having inlet edges which lie in a common annular surface, of a plurality of duplicate nozzles adjacent said buckets for directing elastic fluid therethrough, said nozzles having eXit edges disposed at such an angle with respect to the inlet edges 'of the buckets that the projections .of said nozzle edges on the surface in which the inlet edges of the buckets lie, intersect said inlet edges of vthe buckets.

16. In an elastic fluid turbine, the combination with a rotor having an annular ring of buckets secured thereon, said buckets having inlet e'dges Which lie in a common annular surface, of a plurality of duplicate nozzles adjacent said buckets for directing elastic fluid therethrough, said nozzles hav ing eXit edges disposed at such an angle with respect to the inlet edges of the buckets that the projection of any one of said nozzle Lemme edges on the surface in which the entrant edges of the buckets lie, intersects not less than tWo adjacent entrant edges of the 10 buckets for all positions of the rotor.

In witness whereof, I have hereunto set my hand this 29th day of August, 1922.

WVM. H. ATKINSON. 

